Portion of a shoe midsole



FIG. 1 is a front perspective view of a portion of a shoe midsole showing my new design;

FIG. 2 is a side elevational view of one side thereof; and,

FIG. 3 is a rear perspective view thereof.

The uneven broken line immediately adjacent to the shaded region represents an unclaimed boundary of the design. The uneven broken line showing inside surfaces of the midsole in the shaded region is for illustrative purposes only and forms of part of the claimed design. The uneven broken line showing the remainder of the shoe upper and the shoe sole is for illustrative environment purposes only and forms no part of the claimed design. 

The ornamental design for a portion of a shoe midsole, as shown and described. 